Chelsea have formalised Marina Granovskaia's role at the Europa League winners by confirming Roman Abramovich's long-time senior adviser as a member of the club's plc and executive boards, establishing her as one of the most senior placed women in English football.

The Russia-born Granovskaia has been a key figure behind the scenes at Stamford Bridge since 2010 when she started attending board meetings in an informal capacity, but she will now sit on both the Chelsea plc and the executive boards, with the latter body undertaking the day-to-day running of the club. Her influence has grown significantly over recent years and she attended Monday's press conference with the new manager José Mourinho – whom she had helped reappoint – standing alongside the chairman, Bruce Buck, and the chief executive, Ron Gourlay, in the audience.

Granovskaia is a dual Russian and Canadian national and graduated in 1997 from Moscow State University before beginning work with the Sibneft oil company, then owned by Abramovich. She has worked with the oligarch across his wide range of business interests over the past 16 years, moving to London in 2003 – shortly after the purchase of Chelsea – to deal with his various assets, taking on a de facto chief of staff role. She has also worked closely with another Canadian-Russian national, the Chelsea director Eugene Tenenbaum, who remains a close confidant of Abramovich. Confirmation of her presence as a director on both boards is not related to Mourinho's return, but merely formalises the structure already in place at the club.

She began working more closely on Chelsea matters from 2010, acting as Abramovich's representative in London in support of the board of directors and stepping up her presence both at the club's offices at Stamford Bridge and, most notably, at their Cobham training complex. While the Chelsea owner will normally attend around three of the executive board's monthly meetings over the course of any season – the executive board usually meet at Stamford Bridge, with the football board convening at the training ground – he has a network of advisers on the ground, of whom the multi-lingual Granovskaia has become one of his most trusted.

It is the line of communication between Granovskaia and Abramovich – similar to that enjoyed by Tenenbaum – that has thrust her into this position of relative power. She will speak to the oligarch on other business issues aside from Chelsea but, as the most direct line to the owner whose own interests mean that his visits to Stamford Bridge are relatively rare, she has been key when time has been tight and an immediate decision has been required on the football side. She played a key part in negotiations over the recruitment of players and managers alongside Gourlay and the technical director, Michael Emenalo, was involved in the talks with Liverpool and Benfica to secure Fernando Torres and David Luiz towards the end of the winter transfer window of January 2011, and is understood to have travelled to Madrid in April to discuss Mourinho's return to the club once it became clear he was intent upon leaving the Bernabéu.

The hope is her position on the board will merely simplify communication in advance of Abramovich sanctioning key decisions and, given the role she already plays, her appointment hardly changes the way the club currently functions. Chelsea have a well established, if rather complicated, hierarchical structure under Abramovich's ownership. The plc board now comprises Buck, Tenenbaum, Gourlay and Granovskaia, with that quartet joined on the executive board by the finance and operations director, Chris Alexander, the company secretary, Alan Shaw, and the club secretary, Dave Barnard.

The football club board, meanwhile, comprises Buck, Tenenbaum, Gourlay, Barnard, the football operations director Mike Forde and Emenalo. They focus entirely on football matters, with reports submitted by the manager and medical staff, Emenalo on recruitment and player issues, and, for example, Forde on training techniques and facilities from information he has gleaned visiting institutions around the world. Abramovich usually attends two or three football club board meetings over the course of a season.